1. Field of Invention
This invention relates in general to power supply circuits, and, more particularly, to high-efficiency inverter circuits operable to provide high voltage outputs suitable for powering gas discharge lamps.
2. Description of the Prior Art
As is well known in the art, the main function of an inverter circuit is to convert a direct or DC input voltage into an alternating or AC voltage output. See, for example my U.S. Pat. No. 4,184,128, issued Jan. 15, 1980, and entitled "High Efficiency Push-Pull Inverters"; Myrrey et al. U.S. Pat. No. 3,467,852, issued Sep. 16, 1969, entitled "High Speed Controlled Switching Circuit"; Engel et al. U.S. Pat. No. 3,753,071, issued Aug. 14, 1973, for "Low Cost Transistorized Inverter"; and Suzuki et al. U.S. Pat. No. 4,031,454, issued Jun. 21, 1977, entitled "Transistor Inverter".
In certain applications of inverter circuits, such as energizing fluorescent or other gas discharge lamps, it is important to provide high voltage both for starting ease and efficienct operation. The following U.S. patents are believed to be representative of the prior art relevant to such lamps and energizing circuits therefor:
______________________________________ Patentee Patent No. Issue Date Title ______________________________________ Morley 2,279,635 04/14/42 Luminous Vapor Lamp Miller 2,298,961 10/13/42 Fluorescent Lamp Polevitzky 2,405,518 08/06/46 Illuminating Device Rogers 2,505,993 05/02/50 Fluorescent Electric Lamp Dupuy 2,525,022 10/10/50 Circular Lighting Fixture Baumgartner 2,817,004 12/17/57 Adapter Holder for et al. Circular Lamps Fry 2,878,372 03/17/59 Circular Lighting Fixture Reaves 3,059,137 10/16/62 Screw-in Fluorescent Lighting Fixture Grunwaldt 3,084,283 04/02/63 Transistor-Battery Supply for Gas Discharge Tubes Wenrich 3,155,875 11/03/64 High Frequency Ballast et al. for Fluorescent Lamps Genuit 3,263,122 07/26/66 Current Limiting Inverter Crcts and Apparatus for Operating Electric Discharge Lamps & Other Loads Johnson 3,634,681 01/11/72 Integral Ballast, Lamp- Holder Support and Wireway Piccola 3,704,212 11/28/72 Adjustable Light Fixture for U-Shaped Lamps Anderson 4,093,893 06/06/78 ShortArc Fluorescent Lamp Wheeler 4,093,974 06/06/79 Fluorescent Lampholder Ass'y for Circline Lamp Young et al. 4,173,730 11/06/79 Compact Fluorescent Lamp Unit having Integral Crct Means for DC Operation ______________________________________
While gas discharge lamp units and associated energizing circuits are generally known in the prior art typified by these patents, need has arisen for improved devices of these types, particularly inexpensive, reliable and highly efficient inverter circuits which can be employed to provide high voltage outputs suitable for energizing gas discharge lamps.